Merge pull request #5056 from viktorklang/wip-SI9488-Future.toString-√

SI-9488 - adds the same default toString format to Scala Futures as 2…

4 files changed, 34 insertions, 2 deletions

diff --git a/bincompat-backward.whitelist.conf b/bincompat-backward.whitelist.conf
index 0d85590b41..0770b3cb95 100644
--- a/bincompat-backward.whitelist.conf
+++ b/bincompat-backward.whitelist.conf
@@ -217,6 +217,12 @@ filter {
     {
         matchName="scala.concurrent.impl.Promise$DefaultPromise"
         problemName=MissingTypesProblem
+    },
+    // SI-9488: Due to SI-8362 above, toString was silently changed to the AtomicReference toString implementation,
+    // This is fixed by SI-9488, and this should be safe since the class in question is stdlib internal.
+    {
+        matchName="scala.concurrent.impl.Promise.toString"
+        problemName=MissingMethodProblem
     }
   ]
 }
diff --git a/bincompat-forward.whitelist.conf b/bincompat-forward.whitelist.conf
index a9fbaa7b87..c6cffee846 100644
--- a/bincompat-forward.whitelist.conf
+++ b/bincompat-forward.whitelist.conf
@@ -381,6 +381,12 @@ filter {
     {
         matchName="scala.concurrent.impl.Promise$DefaultPromise"
         problemName=MissingTypesProblem
+    },
+    // SI-9488: Due to SI-8362 above, toString was silently changed to the AtomicReference toString implementation,
+    // This is fixed by SI-9488, and this should be safe since the class in question is stdlib internal.
+    {
+        matchName="scala.concurrent.impl.Promise.toString"
+        problemName=MissingMethodProblem
     }
   ]
 }
diff --git a/src/library/scala/concurrent/impl/Promise.scala b/src/library/scala/concurrent/impl/Promise.scala
index b15601058e..6d2fc5c87c 100644
--- a/src/library/scala/concurrent/impl/Promise.scala
+++ b/src/library/scala/concurrent/impl/Promise.scala
@@ -19,6 +19,10 @@ import java.util.concurrent.locks.AbstractQueuedSynchronizer
 
 private[concurrent] trait Promise[T] extends scala.concurrent.Promise[T] with scala.concurrent.Future[T] {
   def future: this.type = this
+  override def toString: String = value match {
+    case Some(result) => "Future("+result+")"
+    case None => "Future(<not completed>)"
+  }
 }
 
 /* Precondition: `executor` is prepared, i.e., `executor` has been returned from invocation of `prepare` on some other `ExecutionContext`.
diff --git a/test/files/jvm/future-spec/FutureTests.scala b/test/files/jvm/future-spec/FutureTests.scala
index a290af9cd3..efe9c59d7a 100644
--- a/test/files/jvm/future-spec/FutureTests.scala
+++ b/test/files/jvm/future-spec/FutureTests.scala
@@ -24,7 +24,7 @@ class FutureTests extends MinimalScalaTest {
   "A future with custom ExecutionContext" should {
     "shouldHandleThrowables" in {
       val ms = new mutable.HashSet[Throwable] with mutable.SynchronizedSet[Throwable]
-      implicit val ec = scala.concurrent.ExecutionContext.fromExecutor(new scala.concurrent.forkjoin.ForkJoinPool(), {
+      implicit val ec = scala.concurrent.ExecutionContext.fromExecutorService(new scala.concurrent.forkjoin.ForkJoinPool(), {
         t =>
         ms += t
       })
@@ -64,7 +64,7 @@ class FutureTests extends MinimalScalaTest {
       Await.ready(waiting, 2000 millis)
 
       ms.size mustBe (4)
-      //FIXME should check
+      ec.shutdownNow()
     }
   }
 
@@ -543,6 +543,22 @@ class FutureTests extends MinimalScalaTest {
       Await.ready(f, defaultTimeout).value.get.toString mustBe expected.toString
     }
 
+    "should have a decent toString representation" in {      
+      val i = scala.concurrent.forkjoin.ThreadLocalRandom.current.nextInt()
+      val e = new Exception(i.toString)
+      val successString = "Future(Success("+i+"))"
+      val failureString = "Future(Failure("+e+"))"
+      val notCompletedString = "Future(<not completed>)"
+      
+      Future.successful(i).toString mustBe successString
+      Future.failed[Int](e).toString mustBe failureString
+      Promise[Int]().toString mustBe notCompletedString
+      Promise[Int]().success(i).toString mustBe successString
+      Promise[Int]().failure(e).toString mustBe failureString
+      Await.ready(Future(i)(ExecutionContext.global), defaultTimeout).toString mustBe successString
+      Await.ready(Future(throw e)(ExecutionContext.global), defaultTimeout).toString mustBe failureString
+    }
+
   }
 
 }